What is a 'Radial Tank'?

[Ruston]

I've only ever  heard of the Lancashire & Yorkshire Railway 2-4-2T engines being known as Radial Tanks but tofay I bought a book on Hull & Barnsley locomotives, published by the HMRS. On the cover is a H&B Class F2 0-6-2T, built by Kitson & Co. of Leeds. The picture is a maker's coloured photo and the loco is described as a "Hull, Barnsley & West Riding Junction Railway Six-coupled Radial Tank Engine.

 

So, what exactly defines a Radial Tank Engine from any other tank engine?

[pH]

Here's a simple explanation of radial axles:

 

https://en.m.wikipedia.org/wiki/Radial_axle

 

Here's a discussion of modern diesel radial trucks, where each axial behaves 'radially' within the truck, rather than the truck behaving as a single, fixed unit:

 

http://cs.trains.com/trn/f/741/t/132447.aspx

[Steamport Southport]

Someone will come up with a technical answer, but it was the fact that they had radial trucks rather than fixed frames or normal bogies.

 

A radial axle is an axle on a railway locomotive or carriage which has been designed to move laterally, along the arc of a circle, when entering a curve in order to reduce the flange and rail wear.

 

​​From Wikipedia.

 

https://en.wikipedia.org/wiki/Radial_axle

 

 

 

 

Jason

[MarcD]

The Furness described there 0-6-2t as radial tanks but having resently got my hands on some GA drawings it turns out the had bissle trucks. I have some GA drawings for various NER locos that have a true radial axles. Are both correct?

 

Marc

[Steamport Southport]

Two other types that are Radial Tanks.

 

Obviously the LSWR Adams Radial Tank 4-4-2Ts and the LBSC E3/E4/E5/E6 0-6-2Ts.

 

 

 

 

Jason

[Compound2632]

F.W. Webb was a great enthusiast for radial axles - if not their progenitor - and for many years would not go near bogies. Although Crewe wasn't in charge of carriage design for the LNWR, it did, I think, build or supply the components for iron/steel underframes as Wolverton didn't have the capability. This resulted in radial 8-wheel coaches - the two inner axles fixed and the outer axles radial. When well-maintained and very tightly coupled, they are said to have run very smoothly. 

 

Webb's various 2-4-2T and 0-6-2T classes all had radial axles for the carrying wheels. I'm away from my books so not sure about the leading axles of 2-4-0s.

 

T.W. and Wilson Worsdell, with their Crewe training, were, as Furness Wagon notes, also radial enthusiasts.

Edited April 15, 2018 by Compound2632

[PenrithBeacon]

Churchward put a radial axle box on the trailing wheels for his 2-6-2T engines. Collett followed suit.

[jim.snowdon]

A very large proportion of all the locomotives that had a single trailing axle were provided with some form of radial axle. Actual trucks, ie with the axle rigidly mounted in a pivoting frame were unusual and generally confined to locomotives that had to cope with smaller than average curves. Their use on large locomotives in the UK can, I think, be attributed to Stanier, and developed by Bulleid.

 

Jim

[LMS2968]

I think the leading wheels on FWW's 2-4-0s were rigid in the frame, but am open to persuasion. J.A.F Aspinall was one of FWW's premium apprentices and took the same design of radial axle to Horwich, causing FWW to demand royalties when he later found out!

[Compound2632]

A very large proportion of all the locomotives that had a single trailing axle were provided with some form of radial axle. Actual trucks, ie with the axle rigidly mounted in a pivoting frame were unusual and generally confined to locomotives that had to cope with smaller than average curves. Their use on large locomotives in the UK can, I think, be attributed to Stanier, and developed by Bulleid.

 

Jim

 

Is a 2-6-0 large? Presumably the American moguls imported at the turn of the (twentieth) century had Bissel trucks but was Churchward first to use them on a home-grown engine? Or the SECR moguls? I wouldn't be surprised to be told that British engines built for export had been using them for years before this.

 

I think the leading wheels on FWW's 2-4-0s were rigid in the frame, but am open to persuasion. J.A.F Aspinall was one of FWW's premium apprentices and took the same design of radial axle to Horwich, causing FWW to demand royalties when he later found out!

 

I realised I should have included Aspinall in my list of Crewe-trained radial users. As far as I'm aware Adams didn't have a Crewe connection - did he develop the radial axle independently or was he in fact the originator, with Webb taking the idea up? There must have been sufficient differences in the design for Webb to have a patent.

[Ian J.]

Reading up a bit on what a radial axle is/does (as I didn't know before reading this thread), I'm not surprised that the Adams Radial 4-4-2s were the only locomotives found best suited to the Lyme Regis branch.

[Talltim]

It’s funny, other tank engine types with a prefix describe the shape of the tank, side, pannier, well, etc. A newcomer to railways could easily be confused!

Edited April 15, 2018 by Talltim

[coachmann]

The radial axle rides withing its own frame, which in turn is cast like a banana which slides within runners. So the wheels don't just have side play; They also turn in an arc so they are in effect steering the chassis.

 

Simplistic and understandable, I hope.

Edited April 15, 2018 by coachmann

[Grovenor]

jim.snowdon, on 15 Apr 2018 - 09:41, said:

A very large proportion of all the locomotives that had a single trailing axle were provided with some form of radial axle.

 

Is a 2-6-0 large? Presumably the American moguls imported at the turn of the (twentieth) century had Bissel trucks but was Churchward first to use them on a home-grown engine? Or the SECR moguls? I wouldn't be surprised to be told that British engines built for export had been using them for years before this.

Jim was careful to say "trailing axles", thereby excluding leading axles.

Regards

[Ruston]

The radial axle rides withing its own frame, which in turn is cast like a banana which slides within runners. So the wheels don't just have side play; They also turn in an arc so they are in effect steering the chassis.

 

Simplistic and understandable, I hope.

So, it's not a seperate  bogie or a pony truck, it's an axle in a frame within the locomotive's main frames?

[Orion]

 

A picture is worth a thousand words? The outsides of the axleboxes are angled so that when the wheels go into a curve the axle and axleboxes together move sideways with a radial motion.

[Orion]

Heres another example

 

[Compound2632]

Jim was careful to say "trailing axles", thereby excluding leading axles.

Regards

 

Jim, my apologies for not reading carefully enough. Grovenor, thank-you for pointing this out.

[PenrithBeacon]

A very large proportion of all the locomotives that had a single trailing axle were provided with some form of radial axle. Actual trucks, ie with the axle rigidly mounted in a pivoting frame were unusual and generally confined to locomotives that had to cope with smaller than average curves. Their use on large locomotives in the UK can, I think, be attributed to Stanier, and developed by Bulleid.

 

Jim

Churchward used pony trucks on 2-6-0 and 2-8-0 designs, Hughes on the Horwich Mogul, Fowler on his 2-6-4T. There were others too, including Gresley. It’s a mistake too attribute the use of pony trucks to Stanier and Bulleid, then you shouldn’t forget Cartazzi of the GNR either.

Essentially the radial axlebox is an implementation of the inclined plane and that goes back into deep time.

[Michael Edge]

I think the leading wheels on FWW's 2-4-0s were rigid in the frame, but am open to persuasion. J.A.F Aspinall was one of FWW's premium apprentices and took the same design of radial axle to Horwich, causing FWW to demand royalties when he later found out!

 

2-4-0 tender loos normally had fixed leading axles, most tank locos with a single trailing were radial. Notable exceptions were the LNW "Bissel tanks", 0-4-2T with a pony truck and the SR 0-6-2T rebuilds of LBSC E1 0-6-0T - these (E1/R) used spare pony trucks from the Woolwich moguls.

[MarcD]

I though that to until I got the Furness GA's which were described as redial tanks on the GA but when you look at the actual drawing they all have bissel trucks. I thought they would have been similar to the  LNWR/NER type. As the Furness tanks were design by W.F. Pettigrew, who was Adams's chief designer, has anyone had a good look at the Adam's radial GAs?

 

Marc    

[Grovenor]

 As the Furness tanks were design by W.F. Pettigrew, who was Adams's chief designer, has anyone had a good look at the Adam's radial GAs?

Marc    

Post #17 above!

Regards

[jim.snowdon]

Churchward used pony trucks on 2-6-0 and 2-8-0 designs, Hughes on the Horwich Mogul, Fowler on his 2-6-4T. There were others too, including Gresley. It’s a mistake too attribute the use of pony trucks to Stanier and Bulleid, then you shouldn’t forget Cartazzi of the GNR either.

Essentially the radial axlebox is an implementation of the inclined plane and that goes back into deep time.

I was referring to trailing axles, not leading ones.

 

The situation with regard to leading axles is almost exactly the reverse - pony trucks were the normal arrangement, with radial axleboxes used relatively rarely.

 

The Cartazzi arrangement adopted by Gresley is only another variety of radial axlebox.

 

Jim

[The Johnster]

Churchward put a radial axle box on the trailing wheels for his 2-6-2T engines. Collett followed suit.

 

As he also followed suit with the 56xx 0-6-2T, a development of the Rhymney Railway 'R' class.  South Wales 0-6-2T engines in general had radial trucks.

[Wickham Green]

I was referring to trailing axles, not leading ones.

 

The situation with regard to leading axles is almost exactly the reverse - pony trucks were the normal arrangement, with radial axleboxes used relatively rarely.

 

The Cartazzi arrangement adopted by Gresley is only another variety of radial axlebox.

 

Jim

Indeed .... 'cos if you try to fit a pony truck at the rear of a loco you'll find someone's put a firebox where you want the pivot to go !